This invention relates to a casein-based dietetic foodstuff and to a method for its preparation.
The production of a protein concentrate in granulate form from low fat or fat-free edible curds, as well as the use thereof as a dietetic foodstuff, is already known. Such a granulate is normally produced from fresh curds, which are as fat-free as possible, by first mechanically removing a part of the whey and subsequently granulating and drying them. (See, e.g., DAS 1,692,306).
However, the production of these products suffers from numerous difficulties. It is not possible to always obtain a uniformly granular product. Moreover, when the mass obtained after partial removal of the whey is too moist, it cannot be granulated at all since it smears or the overly moist granules stick together. On the other hand, if the material has become too dry, it tends to crumble, whereby, after drying, too high a proportion of dust and fine grains is obtained. Due to such variations in the water content and the varying properties of the curds resulting therefrom, it is difficult to achieve a continuous and reproducible process for granulate production since it is not possible to adjust the water content to constant values by mechanical processes.
Furthermore, the curd starting material is relatively expensive and in some territories, especially in warmer countries, is difficult or even impossible to obtain.
Therefore, attempts have been made to replace the curds partially or completely by casein. However, in these processes, other difficulties arise. Thus, casein alone is difficult to granulate; the granulates obtained are not stable and easily break down to dust after drying. In the stomach, too, such granulates are unstable; their residence time is only about 30 minutes, whereas for the desired dietary purpose, several hours are desired.
A process which employs both curds and casein to obtain a dietetic granulate is also known, i.e., U.S. Application Ser. No. 824,194, filed on Aug. 12, 1977, now U.S. Pat. No. 4,139,642 and its divisional application Ser. No. 952,591 filed on Dec. 22, 1978). Of course, this method suffers from the curd supply problem mentioned above.